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(No Model.) 3 SheetsSheet 1.

G. E. HANIS'OH. BOILING AND PREOIPITATING TOWER. No. 477,755. PatentedJune 28, 1892.

(No Model.) 3 Sheets-Sheet 3.

G. E. HANISUH BOILING AND PRECIPITATING TOWER.

No. 477,755. Patented June 28, 1892.

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1 UNITED STATES PATENT OFFICE.

GUSTAV EMIL I-IANISCH, OF BEIITHEN, GERMANY.

BOILING AND PRECIPITATING TOWER.

SPECIFICATION forming part of Letters Patent No. 477,755, dated June 28,1892. Application filed March 3, 1890- SerialNo. 342,400. (No model.)

To all whom it may concern:

Be it known that I, GUSTAV EMIL HANIscH, a subject of the King of Saxonyand German Emperor, residing in the city of Beuthen, German Empire, haveinvented certain new and useful Improved Boiling and PrecipitatingTowers; and I do hereby declare that the following is a full, clear, andexact description of the invention, which will enable others skilled inthe art to which it appertains to This invention relates to boiling andpre cipitatjng towers or columns for carrying out various chemicalprocesses in which precipitates are obtained from any kind of solutionby the introduction of steam or gas, &c.

It has for its object to providea boiling and precipitating tower whichmay be worked regularly and continuously for a certain time and whichcan be completely discharged and cleaned out withoutloss of time or ofthe substance treated in the tower.

The invention consists in a construction of the boiling andprecipitating tower in two chambers or divisions, so that the onechamher for the boiling-out or precipitating process, closing air-tightand provided with fittings suitable for the purpose, is separated fromthe other chamber, serving as a passage of access and also closingair-tight by a partition formed by closely-shutting plates or doorslocated one above another.

In the accompanying drawings, Figure 1 is a vertical section of aboiling and precipitating tower embodying this invention; Fig. 2, avertical section through line A B of Fig. 1; Fig. 3, a vertical sectionof a portion of the tower to an enlarged scale; Fig. 4, a horizontalsection through line C D of Fig.3; Fig. 5, a vertical section through aportion of the tower with wood blocks arrangedtherein.

The tower consists, substantially, of a boarded shaft of considerableheight and root angular in cross-section. The inside of the tower islined with sheet-lead 1 and made airtight. The tower or boarded shaft isconstructed in two divisions or chambers.

E is the chamber in which solutions or lyes are boiled orprecipitatesobtained therefrom, to which end it is fitted with inclined planes 2,Fig. 2,'or has wood bars 3, Fig. 5, arranged in it. The other chamber Fis without fittings and serves simply as a passage for the workmanengaged in clearing out the boiling and precipitating chamber E. The twochambers .are separated by a partition made up of single wood plates orplanks 4, standing one above another, lined or covered with lead on theinner or chamber E side, and closing airtight, these plates 4 being heldpressed against the shaft-frame by props 5, the edge bearingsnrfaces, aswell as the butt-joint surfaces of the plates 4, being covered withindia-rubber, so as to render a hermetical closure practicable. I

If the tower is intended for the treatment of alkaline instead of acidsolutionsas, for instance, for the boiling or evaporation of weakammonia-water with addition of milr of limeit may be constructed ofplate-iron instead of wood with a lead covering.

In order that it may not be necessary to remove the whole of thepartition from top to bottom when, as may frequently happen, a stoppageor blocking up of the tower takes place at any part of its height,square iron bars 6, covered with lead, are interposed at certaindistances apartsay from two to three yardsto act as bearers each forfrom four to six plates or planks 4. In order, also, to prevent thenecessity of removing the wood bars 3 for the purpose of clearing outthe tower, these must not be placed to cross each other, but must alllie in the same direction, with their ends toward chamber F, to allow ofthe precipitate being withdrawn by means of a long iron tool.

In order, when the cleaning or clearing out operation is in progress, toprevent the precipitate from falling down and accumulating at the bottomin a way to stop up the apparatus, the wood blocks in such a kind of internal arrangement as shown in Fig. 5 are arranged in sets from two tothree yards high, one set above the other, each set being separated by aclear distance of about nine inches. In the clearing-out operation aboard the shape of the cross-section of the tower is slid underneath aset and receives the falling material. The solutions or lyes from whichprecipitates are to be obtained pass into the tower through pipe '7. Thesteam or prec=ipitating gases enter through pipe 8. The waste gases passaway through pipe 9. The precipitaies, &c., are dischargedthrough pipe10. The lye, formed with the precipitate to a thin paste flowing out ofthe tower, with addition of lye from the tower, collects in asettlingtank, Fig. 2, placed lower down. The preoipitate settles to thebottom sooner or later, according to its specific gravity, while clearliquid flows off continuously through upper overflow-pipell. Processesof thiskind have hitherto generally been carried out in fixed cylindersor casings, several of which are combined so as to form one apparatus.though this method of working is said to be continuous, yet each elementof the apparatus is in turn thrown out of work, and to charge and emptyit it must be disconnected from the other elements, during which timeits operation isstopped. 'lherefore,instead of such apparatus it is moreadvantageous and convenient to employ high boilin g-towers, which allowof a very regular and for a certain time continuous working. Inconjunction with small attendance requirements, regularity of working,and profitable consumption of steam or gases ascending from below, thereare-two very important properties possessed by boiling-towers ascompared with cylinders and which for certain processes are of greatimportance and economic value. Taking, for example, the boiling out of asolution of phosphate of lime in sulphurous acid-such as is obtained inthe process of extraction from bones by means of sulphurous acid-it hasbeen observed that in the boiling process expulsion of the sulphurousacid as pure gas and precipitation of the phosphoric acid asterphosphate of calcium, there has been in practice the great drawbackin the use of evaporating-vessels that the most important evolution ofsulphurous acid taking place between and 90 Celsius of temperaturecauses such a violent soap-like froth-l ing that the larger portion ofthe charge has;

to be thrown over to the next vessel of the combined apparatus. Thefrothin g then takes place to a greater extent in the second vessel,

greater still in the third, and so on, as each,

successive vessel has an increased charge. Therefore in practice, inorder to avoid frothing over either, very high vessels are used, or:

these must be worked with a charge of onethird or one-quarter theircapacity.

vantage that the air entering the vessel every time it is charged, say,to the extent of three phosphate solution of 16 Baum strength,

the precipitate contains from fifteen to sixteen per cent. of sulphurousanhydride and the residual lyethat is, the liquid remain- This course,however, presents the great disading behind after the process ofprecipitation from 0.5 to 0.6 per cent. of sulphurous acid, while theboiling out of a similar solution in the tower during a space of time ofalmost two minutes yields a precipitate containing only from seven toeight per cent. of sulphurous acid, corresponding to the quantities ofthe earths and alkalies present, and a residual lye with only 0.25 percent. of sulphurous acid. Consequently the performance of theprecipitating process in the tower is, in addition to continuous workingand a much lower expenditure of steam, of advantage from a double pointof view, as, first, the expelled gas-sulphurous anhydrideaftercondensation of the steam is obtained only in a pure state, and,secondly, the precipitate-is almost perfectly free from sulphurous acid.

There are several chemical processes quite analogous to the examplecited. In most cases the employment of towers would be preferred for theboiling or treatment of lyes or solutions with gases were it not for animportant drawback which has hitherto been the cause of such towersbeing advantageous to a small extent only. This drawback consists intheir liability to a more or less frequent stopping up of their fittingsor passages by the formation of sludge, which renders it necessary toput them out of operation for their thorough discharge and clearing out.Attempts have been made to get over the diffieulty of the clearing ofthe internal fittings or to render this easier by arranging at the sidesof the tower large cleaning-apertures closable with plates and screws;but in this case the clearing out can only be imperfectly accomplished,especially when the sludge cakes to hardness, as it does in many boilingprocesses. There is also the evil that the large number ofcleaning-apertures required are very difficult to keep tight, andconsequently lead to a loss of as.

b In order to allow of boiling and precipitatin g towers of the kindreferred to being easily and thoroughly cleared out without much loss oftime and. without removal of the internal fittings, I construct andoperate them as here inbefore described.

The difficulty of properly closing the cleaning-apertures has led me tothe construction of my double chamber boiling and precipitating tower,the essential feature of which is the removable partition composed ofplates- Wall composed of removable tightly-closing ing toward said sideor wall of shaft E, subplates located one above another, incombinastantially as described and shown. L tion with a fixed bearer toeach set of from In testimony whereof I have signed tins four to sixplates, substantially as described specification in the presence of twosubscrib- 5 and shown. ing witnesses.

3. In a boiling and precipitating tower, a

GUSTAV EMIL HANISCH. shaft E, with a side or wall composed of separateremovable tightly-closing plates located Witnesses: one above another,in combination with par- PETER SPREoKELs,

1o allel wood bars located with their ends point- PAUL DRUOKMI'JLLER.

